Percentages of 24 h retention/accumulation of intravenously injected, 2.8nm GNP (coated either thioglycolic acid or with cysteamine); panel A: data obtained from liver, spleen, lungs, blood, remaining carcass; panel B: data obtained from heart, brain, uterus, kidneys urine and hepato-biliary clearance are given. Data are mean ± SD, n = 4 rats. Significant changes of accumulation of given GNP sizes versus those of the other GNP sizes are indicated as determined by the ANOVA test. (* p<0.05, + p<0.01; α p<0.001).